CN111714100A

CN111714100A - Dual-sensing vital sign monitoring system and method

Info

Publication number: CN111714100A
Application number: CN201910208452.1A
Authority: CN
Inventors: 卢坤涛; 刘众; 乐勇
Original assignee: Shenzhen Granmore Technology Co ltd
Current assignee: Shenzhen Granmore Technology Co ltd
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2020-09-29

Abstract

The invention is suitable for the monitoring field of vital signs, has provided a vital sign monitoring system and method of one pair of sensings, wherein the vital sign monitoring system of one pair of sensings includes: the double-sensing module comprises a main sensor and an auxiliary sensor, the main sensor is used for receiving vital sign signals of a human body and noise signals of environmental micro-vibration, and the auxiliary sensor is only used for receiving the noise signals of the environmental micro-vibration. Signals collected by the main sensor and the auxiliary sensor are respectively filtered and amplified by the filtering and amplifying module in sequence, and two paths of digital signals are obtained by the analog-to-digital conversion device, and the main control chip is used for preprocessing the digital signals and carrying out a heart rate respiration algorithm and storing the obtained real-time heart rate respiration rate value into the memory. The double-sensing vital sign monitoring system provided by the invention has the advantages of high signal-to-noise ratio, low cost, simple structure, strong flexibility and the like.

Description

Dual-sensing vital sign monitoring system and method

Technical Field

The invention belongs to the technical field of vital sign monitoring, and particularly relates to a dual-sensing vital sign monitoring system and method.

Background

The vital sign monitoring device mainly monitors heart rate and respiration rate of people and information such as body movement and bed leaving. Compared with the traditional ECG monitor, the current non-contact and non-wearable vital sign monitoring device has the advantages of convenience and long-term monitoring, and the accuracy can be close to that of the medical monitor. The non-contact vital sign monitoring device mainly utilizes a sensor to acquire micro-vibration signals of a human body, such as a heartbeat ballistocardiogram signal and chest and abdomen movement during respiration, and then converts the micro-vibration signals into electric signals to be processed. Commonly used sensors are piezoelectric ceramics, piezoelectric cables, piezoelectric films, optical fibers, radar, etc. The sensitivity of the sensors to weak vibration signals is very high, so that accurate heart rate and respiration rate values can be obtained.

However, the high sensitivity has the disadvantage that the sensor is also sensitive to disturbances in the external environment. For example, for some noisy environments, the vibration of the environment itself even exceeds the signal of the human body itself, so that the real vital sign signal is submerged, and the detection accuracy of the heart rate and the respiration rate is reduced. More seriously, the false judgment of the existence of people can be caused, and the environmental noise is mistaken to be the vital sign signal. Therefore, in order to adapt the vital sign monitoring device to different environments, the signal-to-noise ratio of the system needs to be improved.

Disclosure of Invention

The embodiment of the invention aims to provide a double-sensing vital sign monitoring system and a double-sensing vital sign monitoring method, which are used for solving the problem that a vital sign monitoring device cannot obtain accurate heart rate and respiratory rate and the like because a sensor is easily interfered by external environment noise when acquiring a micro-vibration signal of a human body in the prior art.

The embodiment of the invention is realized in such a way, and provides a double-sensing vital sign monitoring system, which comprises a double-sensing module, a filtering and amplifying module, an analog-to-digital conversion device, a main control chip and a memory, wherein the double-sensing module comprises a main sensor and an auxiliary sensor, the main sensor is used for receiving vital sign signals and environmental noise signals of a human body, and the auxiliary sensor is set to only receive the environmental noise signals.

Further, the dual sensing module is a thin film type, thin sheet type or cable type sensing structure.

Furthermore, the double sensing modules are of a thin film type sensing structure, the double sensing modules further comprise a shell, contact points, supporting piers, limiting piers and a main board, the contact points are located on the shell and are in contact with the main sensor, the main sensor and the auxiliary sensor respectively form a bridge type structure with the supporting piers and the limiting piers, and the auxiliary sensor is not in contact with the shell or the contact points.

Further, the dual sensing module is a thin-sheet type sensing structure, wherein the dual sensing module further comprises a housing, a contact point and a signal line, wherein the contact point is located on the housing and is in contact with the main sensor, and the auxiliary sensor is not in contact with the housing or the contact point.

Further, two sensing modules are cable formula sensing structure, wherein two sensing modules still include top layer covering, substrate, safety cover and signal line, wherein the safety cover is hard safety cover, sets up to cover on the auxiliary sensor in order to prevent the auxiliary sensor gathers human vital sign signal.

Furthermore, the filtering and amplifying module comprises two filtering and amplifying circuits, the topological structures and the circuit parameters of the two filtering and amplifying circuits are the same, and the PCB wiring is symmetrically arranged, so that the noise caused by the asymmetry of the circuits is reduced to the minimum.

Furthermore, the filtering and amplifying module is a differential amplifying circuit, signals of the main sensor and the auxiliary sensor are directly used as positive and negative inputs of the differential amplifying circuit, environmental common mode noise can be directly filtered out in a circuit mode, and only vital sign signals (differential signals) are amplified.

Another object of an embodiment of the present invention is to provide a dual-sensing vital sign monitoring method, including the following steps:

acquiring sensor data: the method comprises the steps of collecting data of a main sensor and collecting data of an auxiliary sensor;

signal filtering and amplifying: respectively filtering and amplifying signals acquired by a main sensor and an auxiliary sensor;

analog-to-digital conversion: analog signals output by filtering and amplifying signals collected by a main sensor and an auxiliary sensor are respectively subjected to analog-digital conversion;

identifying whether a person exists or not;

recognizing body movement; and

heart rate respiration algorithm.

Further, the step of identifying the presence or absence of a person includes:

acquiring an array M [ n ] of a main sensing signal and an array S [ n ] of an auxiliary sensing signal;

obtaining a Mean value Mean _ M of the main sensing signal and a Mean value Mean _ S of the auxiliary sensing signal;

obtaining the average energy P _ M of the main sensing signal and the average energy P _ S of the auxiliary sensing signal;

the average energy of the two paths of signals is subtracted to obtain the energy difference DP of the signals; and is

And comparing the energy difference of the two paths of signals with a set threshold value DP _ th, judging that the person is present when DP exceeds the threshold value DP _ th, and otherwise, judging that the person is absent.

Further, the body motion recognition step includes:

making difference on the two paths of signals to obtain a main and auxiliary sensing signal difference DMS [ n ];

calculating the number Cnt _ bm of DMS [ n ] which is larger than the set body motion threshold DMS _ th; and is

And comparing the Cnt _ bm with a set threshold Cnt _ th, and judging the body movement when the Cnt _ bm exceeds the threshold Cnt _ th, otherwise, judging the body movement.

Further, the heart rate respiration algorithm step comprises:

carrying out frequency domain transformation and spectrum analysis on the array S [ n ] of the auxiliary sensing signals;

constructing an environmental noise filter;

acquiring a signal M _ filter [ n ] filtered by a main sensor;

performing a heart rate and respiration rate algorithm on the M _ filter [ n ]; and

heart rate and respiration rate are acquired.

Compared with the prior art, the invention has the beneficial effects that: the double-sensing vital sign monitoring system adopts a double-sensing structure to improve the signal-to-noise ratio of the vital sign monitoring system. One sensor is used for receiving vital sign signals of a human body and noise signals of environmental vibration and serves as a main sensor; the other sensor is used only for receiving the noise signal of the environmental vibration as an auxiliary sensor. According to the double-sensing vital sign monitoring method provided by the invention, two groups of data are processed by a certain algorithm, the signal-to-noise ratio of the vital sign signals of the human body can be improved, and the accuracy of the measured heart rate and respiratory rate is high. Compared with the traditional vital sign monitoring system and method, the dual-sensing vital sign monitoring system has the advantages of simple structure, strong flexibility, low cost and the like, and the wireless communication connection with the mobile terminal can be realized through Bluetooth, wifi, zigbee and the like.

Drawings

Fig. 1 is a hardware configuration diagram of a dual-sensing vital signs monitoring system according to an embodiment of the present invention;

fig. 2 is a hardware block diagram of another dual-sensing vital signs monitoring system according to an embodiment of the present invention;

fig. 3 is a hardware block diagram of another dual-sensing vital signs monitoring system according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a thin film type dual sensor module according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a sheet-type dual sensor module according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a cable-type dual sensor module according to an embodiment of the present invention;

fig. 7 is a flowchart of a dual-sensing vital signs monitoring method according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of an algorithm for identifying the presence or absence of a person in FIG. 7 according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a motion recognition algorithm of FIG. 7 according to an embodiment of the present invention; and

fig. 10 is a schematic diagram of a heart rate respiration algorithm of fig. 7 according to an embodiment of the present invention.

In the figure: 1-shell, 2-main sensor, 3-auxiliary sensor, 4-contact point, 5-support pier, 6-limit pier, 7-main board, 8-signal line, 9-surface layer covering material, 10-substrate and 11-protective cover.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the invention provides a double-sensing vital sign monitoring system which comprises a double-sensing module, a filtering and amplifying module, an analog-digital conversion device, a main control chip, a memory and a wireless communication module, wherein the double-sensing module comprises a main sensor and an auxiliary sensor, the main sensor is used for receiving a vital sign signal (main signal) of a human body and a noise signal (background signal) of environmental micro-vibration, and the auxiliary sensor is only used for receiving the noise signal (background signal) of the environmental micro-vibration. Fig. 1 is a hardware structure diagram of a dual-sensing vital sign monitoring system according to an embodiment of the present invention, and it can be seen from the diagram that original signals acquired by a main sensor and an auxiliary sensor are respectively filtered and amplified by a filtering and amplifying module, an analog-to-digital conversion device is used for converting analog signals output by the filtering and amplifying module into digital signals, a main control chip is used for preprocessing the digital signals and performing a heart rate and respiration rate algorithm, and storing an obtained real-time heart rate and respiration rate value in a memory, and the main control chip may be connected to a client terminal through a wireless communication module.

Fig. 2 is a hardware structure diagram of a dual-sensing vital sign monitoring system according to another embodiment of the present invention, and it can be seen from the diagram that the filtering and amplifying module in fig. 1 is replaced with a differential amplifying circuit, so that signals of the main sensor and the auxiliary sensor can be directly used as positive and negative inputs of the differential amplifying circuit, common-mode signals of environmental noise can be directly filtered out by a circuit, and vital sign signals are amplified as differential-mode signals, thereby improving the signal-to-noise ratio of the vital sign monitoring system.

Fig. 3 shows a hardware structure diagram of a dual-sensing vital signs monitoring system combining fig. 1 and fig. 2 according to an embodiment of the present invention, and it can be seen from the diagram that the vital signs monitoring system in this embodiment employs a filtering and amplifying module and a differential amplifying circuit, so that the advantages of low cost and high flexibility of the algorithm processing method in fig. 1 and high signal-to-noise ratio of the signal obtained in fig. 2 are combined.

Specifically, the dual sensing module in the vital signs monitoring system provided by the embodiment of the present invention further includes a film-type, a sheet-type or a cable-type sensor, such as a piezoelectric film, a piezoelectric ceramic, a piezoelectric cable, an optical fiber sensor, and the like.

Fig. 4 shows a schematic structural diagram of a thin-film dual sensor module, which may be a piezoelectric thin film. As shown in fig. 4, the dual sensing module includes a housing 1, a main sensor 2, an auxiliary sensor 3, a contact point 4, a support pier 5, a limit pier 6, and a main board 7, wherein the main sensor 2, the auxiliary sensor 3, the contact point 4, the support pier 5, the limit pier 6, and the main board 7 are all disposed inside the housing 1. The housing 1 may be made of a rigid material, such as metal or plastic. A contact point 4 is located on the housing 1 and is in contact with the main sensor 2. Vital signs of the human body are transmitted through the housing 1 via the contact point 4 to the main sensor 2. The main sensor 2 or the auxiliary sensor 3, the support bridge pier 5 and the limit bridge pier 6 respectively form a bridge type sensing structure. The support pier 5 is used for supporting the sensor, so that the sensor has enough space to generate micro deformation. The limiting bridge pier 6 is used for limiting, and prevents the sensor from being damaged due to external overlarge impact. Since the secondary sensor 3 is not in contact with the contact point 4 on the housing, the vital sign signal cannot be transmitted to the secondary sensor 3, so that the secondary sensor 3 can only receive a noise signal of the environment, i.e. a background signal. The sensors may be rivets or PCB traces (not shown) that transmit signals directly to the motherboard 7.

Fig. 5 shows the structure of a sheet-like dual sensor module, which may be a piezoelectric ceramic. During preparation, the piezoelectric material is attached to the metal bottom to form a sheet structure. In this embodiment, the dual sensing module includes a housing 1, a main sensor 2, an auxiliary sensor 3, a contact point 4, and a signal line 8. The housing 1 may be made of a rigid material, such as metal or plastic. The contact point 4 is located inside the housing 1 and contacts the housing 1 while contacting the main sensor 2, and the contact point 4 is not provided on the sub sensor and does not contact the housing 1, as in the above-described embodiment. Vital signs of the human body are transmitted through the housing 1 via the contact point 4 to the main sensor 2. Since the secondary sensor 3 is not in contact with the contact point 4 on the housing, the vital sign signal cannot be transmitted to the secondary sensor 3, so that the secondary sensor 3 can only receive a noise signal (background signal) of the environment. The sensor may be connected to the signal line 8 by means of a wire to output a signal. The signal line 8 is used for connection with the main chassis.

Fig. 6 shows a schematic structural diagram of a cable-type dual sensing module, that is, the dual sensing module includes a cable-type sensor, where the cable-type sensor may be a piezoelectric cable or an optical fiber sensor. As shown in fig. 6, the dual sensing module includes a main sensor 2, an auxiliary sensor 3, a signal line 8, a surface covering 9, a substrate 10, and a protective cover 11. The signal line 8 is used for being connected with the main machine box, the surface layer covering 9 and the substrate 10 are bonded together to form a thin pad-shaped sensing device, and the protective cover 11 is a hard protective cover and is used for preventing the auxiliary sensor 3 from collecting vital sign signals of a human body. In fig. 6, the signal line 8 is connected to both the main sensor 2 and the sub sensor 3.

Specifically, the filtering and amplifying module adopted in the embodiment of the invention comprises two filtering and amplifying circuits, the topological structures and the circuit parameters of the two filtering and amplifying circuits are completely consistent, and the PCB wiring keeps symmetrical, so that the noise caused by the asymmetry of the circuits can be reduced to the lowest. The filter is usually a band-pass filter, the frequency band is 0.1 Hz-30 Hz, and the frequency band is the main frequency band of the vital sign signals of the human body, so the noise of other frequency bands can be filtered.

In particular, the memory used in the embodiment of the present invention is used to store the result of each calculation of the vital sign signal, such as time, heart rate, respiration rate, bed exit and body movement, so that the vital sign data of a period of time can be derived periodically, so that the user can query the data and make further analysis.

Further, the wireless communication module used in the embodiment of the present invention may be bluetooth, wifi, or zigbee.

An embodiment of the present invention further provides a dual-sensing vital sign monitoring method, which is applied to a dual-sensing vital sign monitoring system, and as shown in fig. 7, the method specifically includes the following steps:

and S1, data acquisition: 21 represents main sensor data acquisition, 31 represents auxiliary sensor data acquisition, and the main sensor data acquisition and the auxiliary sensor data acquisition are carried out simultaneously;

s2 signal filtering and amplifying: 22 represents the filtering and amplification of the signal collected by the main sensor, and 32 represents the filtering and amplification of the signal collected by the auxiliary sensor;

s3 analog-to-digital conversion: 23 corresponds to the analog signal output by filtering and amplifying the signal acquired by the main sensor), and 33 corresponds to the analog signal output by filtering and amplifying the signal acquired by the auxiliary sensor;

40: identifying whether a person exists or not;

50: recognizing body movement;

60: a heart rate respiration algorithm;

70: and (4) storing data.

Specifically, the method comprises the steps that data are acquired by a sensor (including a main sensor and an auxiliary sensor at the same time), then two acquired signals are filtered, amplified and subjected to analog-to-digital conversion, then the existence of the human body is identified and judged by an algorithm for the two digital signals, if the human body is judged to be the human body, the human body is identified, when the identification result is non-human body movement, the human body is in a stable state, then the heart rate and the respiratory rate are calculated, and finally the accurate heart rate and respiratory rate are obtained. Meanwhile, the storage stores data such as existence information, body movement information, heart rate and breathing rate in the process, so that a user can inquire the data and further analyze the data.

Further, referring to fig. 8, the algorithm for identifying the presence or absence of a person in step 40 in fig. 7 specifically includes: 411 obtains an array M [ n ] of the main sensing signal, 412 obtains an array S [ n ] of the auxiliary sensing signal, 421, 422 respectively calculate the average value of the two arrays, obtain the average value Mean _ M and Mean _ S of the main sensing signal, 431, 432 respectively calculate the average value of the energy of the two paths of signals, obtain the average energy P _ M of the main sensing signal and the average energy P _ S of the auxiliary sensing signal, 44 is to make difference to the average energy of the two paths of signals, and obtain the energy difference DP of the signals. And 45, comparing the energy difference of the two signals with a set threshold value DP _ th, and judging that the person is present when DP exceeds the threshold value DP _ th, or judging that the person is absent.

Wherein, the calculation formula of the signal mean value is as follows:

the average energy of the signal is calculated as:

where n is the length of the acquired array of signals.

The calculation formula of the energy difference of the two paths of signals is as follows:

DP＝P_M-P_S

fig. 9 shows specific steps of the body motion recognition algorithm of step 50 in fig. 7, which specifically includes: 511 firstly obtaining an array M [ n ] of the main sensing signals, 512 obtaining an array S [ n ] of the auxiliary sensing signals, and 52 subtracting the two paths of signals to obtain a main and auxiliary sensing signal difference DMS [ n ]. 53, calculating the number Cnt _ bm of DMS [ n ] which is larger than the set body motion threshold DMS _ th, 54 comparing Cnt _ bm with the threshold Cnt _ th, when Cnt _ bm exceeds the threshold Cnt _ th, determining the body motion, otherwise, determining the body motion.

The calculation formula of the main and auxiliary sensing signal difference is as follows:

DMS[n]＝M[n]-S[n]，

where n is the length of the acquired array of signals.

Fig. 10 shows the specific steps of the heart rate and respiration rate algorithm of step 60 in fig. 7, which include: 64, firstly obtaining an array M [ n ] of the main sensing signal, 61, obtaining an array S [ n ] of the auxiliary sensing signal, 62, then carrying out frequency domain transformation and spectrum analysis on the array S [ n ] of the auxiliary sensing signal to obtain a frequency spectrum of the environmental noise, and then analyzing the frequency spectrum to obtain a peak of the frequency spectrum, namely a main energy concentration frequency band of the environmental noise. And then 63, constructing an environment noise filter, and filtering a main noise concentration frequency band in the environment by passing the array M [ n ] of the main sensing signals acquired by 64 through the filter, so as to obtain signals M _ filter [ n ] filtered by the main sensor 65. Because the signal M _ filter [ n ] filters out the noise frequency band of the environment, the energy of the vital sign signal of the human body is more obvious, namely the signal-to-noise ratio of the system is improved. The filtered signal is then subjected 66 to a heart rate and respiration rate algorithm 67 to derive the heart rate and respiration rate.

Compared with the traditional vital sign monitoring system and method, the double-sensing vital sign monitoring system and method provided by the embodiment of the invention have the advantages of high signal-to-noise ratio, low cost, simple structure, strong flexibility and the like.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides a vital sign monitoring system of two sensing, includes two sensing modules, filtering amplification module, analog-to-digital conversion device, main control chip and memory, two sensing modules include main sensor and assistance sensor, main sensor is used for receiving human vital sign signal and environmental noise signal, assistance sensor sets up to only receiving environmental noise signal.

2. The dual-sensing vital signs monitoring system of claim 1, wherein the dual-sensing module is a thin film, thin sheet, or cable sensing structure.

3. The dual-sensing vital signs monitoring system of claim 2, wherein the dual-sensing module is a thin film sensing structure, wherein the dual-sensing module further comprises a housing, a contact point, a supporting bridge pier, a limiting bridge pier, and a main plate, wherein the contact point is located on the housing and contacts the primary sensor, the primary sensor and the secondary sensor form a bridge structure with the supporting bridge pier and the limiting bridge pier, respectively, and the secondary sensor does not contact the housing or the contact point.

4. The dual-sensing vital signs monitoring system of claim 2, wherein the dual-sensing module is a wafer-style sensing structure, wherein the dual-sensing module further comprises a housing, a contact point, and a signal wire, wherein the contact point is located on the housing and is in contact with the primary sensor, and wherein the secondary sensor is not in contact with the housing or the contact point.

5. The dual-sensing vital signs monitoring system of claim 2, wherein the dual-sensing module is a cable-based sensing structure, wherein the dual-sensing module further comprises a cover, a substrate, a protective cover, and signal wires, wherein the protective cover is a rigid protective cover configured to cover the secondary sensor to prevent the secondary sensor from collecting the vital signs of the human body.

6. The dual-sensing vital signs monitoring system according to claim 1, wherein the filtering and amplifying module comprises two filtering and amplifying circuits, the two filtering and amplifying circuits have the same topology and circuits, and the PCB is symmetrically disposed in terms of wiring, so as to minimize the noise introduced by the asymmetry of the circuits, the filtering and amplifying module is a differential amplifying circuit, and the signals of the main sensor and the auxiliary sensor are directly used as positive and negative inputs of the differential amplifying circuit, so as to filter the ambient common mode noise directly by way of the circuits, thereby only amplifying the vital signs.

7. A dual-sensing vital signs monitoring method, comprising the steps of:

identifying whether a person exists or not;

recognizing body movement; and

heart rate respiration algorithm.

8. The dual-sensing vital signs monitoring method of claim 7, wherein the identifying the presence or absence step comprises:

9. The dual-sensing vital signs monitoring method of claim 7, wherein the body motion identifying step comprises:

10. The dual-sensing vital signs monitoring method of claim 7, wherein the heart rate respiration algorithm step comprises:

constructing an environmental noise filter;

acquiring a signal M _ filter [ n ] filtered by a main sensor;

heart rate and respiration rate are acquired.